某低品位高铁铝土矿焙烧—碱浸预脱硅试验.

张笑天; 徐璐; 李超; 李昃霖; 杨耀辉; 徐莺; 冀成庆

In view of the characteristics of low aluminum, high silicon and high iron in a bauxite ore in Yunnan province, a high aluminum-silicon ratio aluminum concentrate was obtained by roasting-alkali leaching pre-desilication process. The effects of roasting temperature, roasting time, Na2O concentration, alkali leaching time and liquid-solid ratio on pre-desilication were investigated. Under the optimal pre-desilication conditions including roasting temperature of 1 050°C, roasting time of 30 minutes, concentration of leaching agent Na2O of 80 g/L, leaching time of 90 minutes, and liquid-solid ratio of L/S=8 mL/g, the Al-Si ratio of low-grade bauxite can be increased from 4. 08 to 17. 98, and the desilication rate is up to 77. 31%, the relative dissolution rate of alumina in pre-desilicated concentrate can reach 94. 56%, and the dissolution effect is ideal. Combined with thermogravimetric differential scanning calorimetry, X-ray diffraction analysis, infrared spectroscopy and other characterization methods, the mechanism of pre-desilication by roasting-alkali leaching was analyzed. The results show that improvement of the Al-Si ratio of bauxite is due to the fact that the kaolin-type silicate minerals in the raw ore can be first converted into alkali-soluble amorphous SiO2 by roasting, and the efficient separation of aluminum silicon can be achieved by atmospheric pressure alkaline leaching, and aluminum concentrate with high aluminumsilicon ratio can be obtained.

SILICATE minerals; DIFFERENTIAL scanning calorimetry; ROASTING (Metallurgy); IRON ores; ATMOSPHERIC pressure; ALUMINUM silicates

Nonferrous Metals (Extractive Metallurgy), 2025, Issue 1, p77

1007-7545

Academic Journal

10.20237/j.issn.1007-7545.2025.01.011